China faced a barrage of international condemnation from London to Canberra yesterday after it was revealed that it had launched a missile attack on an ageing weather satellite, a test that threatened to open a "Star Wars" space race.

Formal protests were lodged with the Beijing government, accompanied by expressions of concern from world leaders, including Tony Blair. The Bush administration is privately seething over the event and is believed to be preparing to turn the incident into a major diplomatic spat.

The concern in the US is that the satellite-killing missile test - said by the US national security council to have been carried out on January 11 - demonstrated China has the capability to knock out its military satellite system, which the Pentagon depends on for navigation and surveillance.

American military and diplomatic analysts said a Chinese attack on about 40 to 50 satellites in low orbit round the world would leave the country's military blinded within a matter of hours.

But others, more sceptical about US policy, insist China had a right to challenge the US's effective monopoly of space. They noted that Beijing has repeatedly pressed for the US to sign agreements outlawing arms in space, overtures Washington has repeatedly rejected.

A Chinese government spokesman, Liu Jianchao, refused to confirm the missile strike had taken place. He said he could not comment because he had no knowledge of such a test. He insisted China supported the peaceful use of space.

The Russian government, which claims to favour demilitarisation of space, expressed doubts about the nature of the test, claiming it was only a rumour that it was a demonstration of an anti-satellite capability. Its defence minister, Sergei Ivanov, said: "I'm afraid that it didn't have an anti-satellite basis. And, maybe, it's good that it didn't."

But the US, Britain, Japan, Australia and other countries had no doubts. Downing Street, while acknowledging China had broken no treaties, expressed dismay that it gave no advance warning of its action.

A No 10 spokesman revealed that Whitehall had protested on Wednesday, arguing that the test is "inconsistent" with Beijing's earlier assurances to the UN on the military use of space, and will add to the space debris problem.

Downing St said: "We don't believe that this does contravene international law. What we are concerned about, however, is lack of consultation and we believe that this development of this technology and the manner in which this test was conducted is inconsistent with the spirit of China's statements to the UN and other bodies on the military use of space."

The destruction of the Chinese satellite was the first such attack in space since the US carried out a similar test in 1985, when Ronald Reagan was pursuing the Star Wars anti-missile defence programme.

The US, which has been trying to establish a closer relationship with China, has been reluctant recently to criticise Beijing but on Thursday lodged a formal protest. Relations between the US and China have been improving since a stand-off in 2001 when a US surveillance aircraft was forced to land on Hainan island.

Dana Perino, the deputy White House press secretary, said yesterday that Chinese officials had not yet responded to concerns expressed by the US. "We do want cooperation on a civil space strategy, so until we hear back from them or have more information, I don't have any more to add," she said.

Although China offers no threat at present, the fear is that if there were a stand-off over Taiwan, the Chinese might be tempted by the option of destroying US satellites. Worry was also expressed by China's near neighbours, Japan and South Korea. Shinzo Abe, the Japanese prime minister, said "We must use space for peace. We are asking the Chinese government about the test."

Alexander Downer, the Australian foreign minister, who was on a visit to New York, said Beijing's ambassador to Australia, Fu Ying, had been called in for an explanation.

"Our concern about this is that to have a capacity to shoot down satellites in outer space is not consistent with ... the traditional Chinese position of opposition to the militarisation of outer space," Mr Downer said.

The test has come as "a bit of a nasty shock", according to Kerry Brown, China expert and associate fellow at the international affairs thinktank Chatham House, in London. Politically, it is a sign that China will be extending its commercial and economic power to more military areas, he said.

Mr Brown could not see any particular significance in the timing but he thought similar events would be more likely in the future. "China is asserting its capacity, showing its ability to be autonomous and not needing to stand in anyone's shadow."

Some analysts suggested yesterday that the test was a warning shot directed at US operations in north-east Asia and America's allies in the region, but played down the immediate implications for a future "Star Wars" crisis or a US-Chinese arms race.

The leading Liberal Democrat expert, Lord Wallace, said that the Chinese move had no direct impact on European security but would be likely to affect Europe because of the effect it would have on the US where a strong Republican lobby believes China is America's main threat.

"It is likely to feed back into the anti-missile defence debate," Lord Wallace predicted, making the US sensitive to EU military and hi-tech exports to China as it was during the largely symbolic row over the arms embargo several years ago.